Performance Optimized Wedge Wide Sealed Dual 15" Enclosure Stereo Integrity SQL-15 · Dual 15" Sealed enclosure

Yes, both: the dual 2 and dual 4 ohm versions share the 15.55 in frame, the 14.17 in cutout and the 7.4 in mounting depth, and the motor clears the cabinet with 3.32 in to spare. Run two of the same coil so the chambers match.

Any other 15, no. The airspace is worked out from the SQL-15's own Qts and Vas, and a different woofer that happened to drop into the hole would not see the alignment printed on this page.

2.00 cubic feet is the same 2.00 cubic feet per chamber as the standard dual wedge, PO 15D-S W SQL, so the wide version sounds the same and only the cabinet shape changes. On Stereo Integrity's figures (Fs 33.0 Hz, Qts 0.57, Vas 59.4 liters) that is Qtc 0.816 with half power at 41.8 Hz. Above Qtc 0.707 the response carries a small lift near 47 Hz before the rolloff, and F3 sits below fc.

The face is fixed at 44 by 18, so depth is the only free dimension.

Stereo Integrity rates the SQL-15 at 1000 watts RMS per driver, so target 700 to 1000 watts RMS per driver at the final load.

A pair lands on 0.5 ohm with all four coils in parallel, 2 ohms as series pairs in parallel, or 8 ohms all in series with dual 2 ohm drivers; 1, 4 or 16 ohms the same three ways with dual 4 ohm drivers. Anything under 1 ohm, and many amplifiers at 1 ohm, is outside what the amplifier is built for; series wiring is the safe default. Confirm your amplifier's minimum stable impedance first.

PO 15D-S W SQL is the standard dual. This wide version holds the drivers on a 44 by 18 inch face, so the cabinet is 17.38 inches deep at the base instead of going deeper on a narrower face. Pick the one that fits the floor.

The airspace per chamber is the same, so the two sound alike.

Two drivers sharing one sealed volume load each other: each driver's compression stroke becomes the pressure the other works against, which blurs the alignment either would have alone. A bonded full-height 3/4 inch divider gives each driver its own 2.00 cubic feet and its own polyfill.

It also means a failure in one driver does not unload the other, and the alignment on this page is the alignment in each chamber, not an average across a shared box.

Anechoic F3 is 41.8 Hz per chamber, with system resonance at 47.2 Hz. Above Qtc 0.707 the response carries a small lift near 47 Hz before the rolloff, and F3 sits below fc.

Those figures exclude cabin gain. In a vehicle the cabin's transfer function adds real output below 50 Hz, so in-vehicle response runs deeper than the numbers above.

No. Polyfill is already installed in both chambers as a light wall lining to control internal reflections, and the quantity is chosen so it does not change the acoustic volume.

Do not add more. Packing a sealed box with fill makes it behave as though it were larger, which walks the alignment away from the 2.00 cubic feet per chamber this cabinet was built to.

No drivers. This is an enclosure only. You receive the cabinet finished in plush black carpet with the gloss black acrylic baffle insert, one side-mounted pre-wired terminal cup to both positions, the polyfill lining already in place, and stainless machine screws.

Yes, the threaded inserts are installed: they are pressed into the baffle at every mounting location for the SQL-15 before it ships, so the drivers bolt straight in. The pair of Stereo Integrity SQL-15 is purchased separately.